Buggy code:
public class ASkyBlock extends JavaPlugin { private boolean newIsland = false ; private static ASkyBlock plugin ; private static World acidWorld = null ; private File playersFolder ; private FileConfiguration challengeFile = null ; private File challengeConfigFile = null ; private Challenges challenges ; private FileConfiguration locale = null ; private File localeFile = null ; private YamlConfiguration welcomeWarps ; private HashMap < UUID , Object > warpList = new HashMap < UUID , Object > ( ) ; private Map < UUID , Integer > topTenList = new HashMap < UUID , Integer > ( ) ; private PlayerCache players ; PotionEffectType acidPotion ; private Listener warpSignsListener ; private Listener lavaListener ; HashSet < UUID > fallingPlayers = new HashSet < UUID > ( ) ; Biomes biomes ; private GridManager grid ; private boolean debug = false ; private HashMap < UUID , List < String > > messages = new HashMap < UUID , List < String > > ( ) ; private YamlConfiguration messageStore ; private boolean calculatingLevel = false ; protected static ASkyBlock getPlugin ( ) { } protected Challenges getChallenges ( ) { } protected PlayerCache getPlayers ( ) { } protected static World getIslandWorld ( ) { } public File getPlayersFolder ( ) { } protected void deletePlayerIsland ( final UUID player , boolean removeBlocks ) { } protected boolean topTenShow ( final Player player ) { } @ Override public ChunkGenerator getDefaultWorldGenerator ( final String worldName , final String id ) { } protected static Location getLocationString ( final String s ) { } protected static String getStringLocation ( final Location l ) { } protected Location getSafeHomeLocation ( final UUID p ) { } protected void homeSet ( final Player player ) { } protected boolean homeTeleport ( final Player player ) { } protected boolean islandAtLocation ( final Location loc ) { } protected boolean isNewIsland ( ) { } protected void setNewIsland ( boolean newIsland ) { } protected static boolean isSafeLocation ( final Location l ) { } protected static void saveYamlFile ( YamlConfiguration yamlFile , String fileLocation ) { } protected static YamlConfiguration loadYamlFile ( String file ) { } protected void loadWarpList ( ) { } protected void saveWarpList ( ) { } protected boolean addWarp ( UUID player , Location loc ) { } protected void removeWarp ( UUID uuid ) { } private void popSign ( Location loc ) { } protected void removeWarp ( Location loc ) { } protected boolean checkWarp ( Location loc ) { } protected Set < UUID > listWarps ( ) { } protected Location getWarp ( UUID player ) { } protected void loadPluginConfig ( ) { } @ Override public void onDisable ( ) { } @ Override public void onEnable ( ) { } protected boolean playerIsOnIsland ( final Player player ) { } protected boolean isOnIsland ( final Player owner , final Player target ) { } protected boolean locationIsOnIsland ( final Player player , final Location loc ) { } protected Location locationIsOnIsland ( final Set < Location > islandTestLocations , final Location loc ) { } protected void registerEvents ( ) { } protected void unregisterEvents ( ) { } protected void restartEvents ( ) { } protected void removeMobs ( final Location l ) { } protected void removeMobsFromIsland ( final Location loc ) { } protected boolean transferIsland ( final UUID oldOwner , final UUID newOwner ) { if ( players . hasIsland ( oldOwner ) ) { Location islandLoc = players . getIslandLocation ( oldOwner ) ; players . setHasIsland ( newOwner , true ) ; players . setIslandLocation ( newOwner , islandLoc ) ; players . setTeamIslandLocation ( newOwner , null ) ; players . setHasIsland ( oldOwner , false ) ; players . setIslandLocation ( oldOwner , null ) ; players . setTeamIslandLocation ( oldOwner , islandLoc ) ; Island island = grid . getIslandAt ( islandLoc ) ; if ( island != null ) { grid . setIslandOwner ( island , newOwner ) ; } <START_BUG> while ( topTenList . values ( ) . remove ( oldOwner ) ) ; <END_BUG> return true ; } return false ; } protected void topTenLoad ( ) { } protected void topTenAddEntry ( UUID ownerUUID , int level ) { } protected void topTenRemoveEntry ( UUID ownerUUID ) { } protected void topTenCreate ( ) { } protected void topTenSave ( ) { } protected void saveDefaultChallengeConfig ( ) { } protected void reloadChallengeConfig ( ) { } protected FileConfiguration getChallengeConfig ( ) { } protected void saveChallengeConfig ( ) { } protected void saveDefaultLocale ( ) { } protected void reloadLocale ( ) { } protected FileConfiguration getLocale ( ) { } protected void saveLocale ( ) { } protected void tellOfflineTeam ( UUID playerUUID , String message ) { } protected void tellTeam ( UUID playerUUID , String message ) { } protected boolean setMessage ( UUID playerUUID , String message ) { } protected List < String > getMessages ( UUID playerUUID ) { } protected void saveMessages ( ) { } protected boolean loadMessages ( ) { } protected static String prettifyText ( String ugly ) { } protected static float blockFaceToFloat ( BlockFace face ) { } protected void resetPlayer ( Player player ) { } protected String getWarpOwner ( Location location ) { } protected void setFalling ( UUID uniqueId ) { } protected void unsetFalling ( UUID uniqueId ) { } protected boolean isFalling ( UUID uniqueId ) { } protected boolean setIslandBiome ( Location islandLoc , Biome biomeType ) { } protected Biomes getBiomes ( ) { } protected Location getClosestIsland ( Location location ) { } public boolean isCalculatingLevel ( ) { } public void setCalculatingLevel ( boolean calculatingLevel ) { } public GridManager getGrid ( ) { } No newline ; at end ; of file ; }

Fix:
topTenList . remove ( oldOwner ) ;